Data processing systems are usually provided with a graphical user interface (GUI) to allow a user to control the data processing system and to present the results of user actions on the system display. In a graphical user interface, applications and data are generally presented as objects depicted on a user interface. A user is then provided with a graphical, intuitive interface to a complex data processing system which permits graphic selection of depicted objects and manipulation of applications corresponding to those objects.
It is usually possible to simultaneously execute several software applications. The execution of multiple applications simultaneously is often referred to as "multitasking". It is desirable in such environments to allow the user to view some or all of the applications simultaneously. This is often accomplished by the utilization of the concept of "windows" wherein all or part of multiple applications are displayed in separate viewports of a computer system video display system. It is known to have multiple software applications present on a computer display simultaneously, one or more of which may be active at any given time, and which may be displayed in a window or icon.
There may be several windows simultaneously present on the desktop with each window displaying information that is generated by a different application program. Each application program presents information to the user through its window by drawing images, graphics or text within the window region. The user, in turn, communicates with the application by pointing at graphical objects in the window with a pointer that is controlled by a pointing device, such as a mouse, and then selecting the objects, or by typing information via a keyboard associated with the monitor. Selection of the objects may be effected by actuating the mouse to move the pointer onto or near the objects and pressing and quickly releasing, i.e. clicking, a button on the mouse, or by manipulating a cursor via the keyboard.
These user interface objects may be easily manipulated utilizing a standard set of interface commands. For example, the user may move the windows around on the display screen, change their sizes and appearances, shrink down a window to a so-called icon, rearrange the objects with respect to their relative background/foreground position so as to arrange the desktop in a convenient manner, etc.
There are a number of different graphical user interface environments commercially available which utilize the arrangement described above. These environments include the System 7 operating system developed by Apple Computer, Inc. (System 7 is a trademark of Apple Computer, Inc.), the Windows graphical user interface developed by the Microsoft Corporation (Windows is a trademark of Microsoft Corporation) and the OS/2 Presentation Manager developed by International Business Machines Corporation (OS/2 and Presentation Manager are trademarks of International Business Machines Corporation).
A problem in a graphical user interface is that when several applications are opened simultaneously, the desktop may assume a cluttered appearance. Some of the windows can overlay other windows, or other graphical elements, such as icons, which are displayed on the desktop. Therefore the user needs to move the foreground windows to operate on hidden elements. Furthermore, if more than one window should be used at the same time, it is necessary to arrange those windows to allow simultaneous interaction.
It is known in graphical user interfaces to provide automated techniques, which avoid the need to manually arrange each single window.
The two most popular techniques are called "tile" and "cascade". Both of them provide an automated arrangement of windows on the desktop, but present some drawbacks.
The tile technique, as shown in FIG. 1, modifies the size of each window and arranges all the windows side by side and top to bottom. It uses the whole desktop area, allowing the user to work with many windows at the same time, without overlaps, but completely hiding the desktop and all the other graphical elements. The windows usually have all the same size, which is dependent on the number of windows to be arranged. Therefore, if many windows are arranged using the tile technique, each window becomes quite small.
The cascade technique, as shown in FIG. 2, arranges the windows so that each window is offset on two sides from the window it overlaps. The windows appear to be stacked, one behind the other. This technique minimizes the desktop area where windows are displayed, but makes it difficult to work with two windows at the same time and results in substantial overlap of the windows.